public class Test6 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        String str = "123";
        System.out.println(strConvert(str));
    }
    
    public static String strConvert(String source){
        String object = "";
        char[] sArray = source.toCharArray();
        for (int i = 0; i < sArray.length; i++) {
            object += Character.toString(sArray[i]) + ",";
        }
        return object.substring(0,object.lastIndexOf(","));
    }

}